scholarly journals Identifying heterotic groups and testers for hybrid development in early maturing yellow maize ( Zea mays ) for sub‐Saharan Africa

2020 ◽  
Vol 139 (4) ◽  
pp. 708-716 ◽  
Author(s):  
Benjamin Annor ◽  
Baffour Badu‐Apraku ◽  
Daniel Nyadanu ◽  
Richard Akromah ◽  
Morakinyo A. B. Fakorede
Keyword(s):  
Zea Mays ◽  
Sub Saharan Africa ◽  
Heterotic Groups ◽  
Early Maturing ◽  
Sub Saharan ◽  
Hybrid Development

scholarly journals Genetic diversity and population structure of early and extra-early maturing maize germplasm adapted to sub-Saharan Africa

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Baffour Badu-Apraku ◽  
Ana Luísa Garcia-Oliveira ◽  
César Daniel Petroli ◽  
Sarah Hearne ◽  
Samuel Adeyemi Adewale ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Inbred Lines ◽  
Snp Markers ◽  
Rapid Expansion ◽  
Sub Saharan Africa ◽  
Heterotic Groups ◽  
Breeding Programs ◽  
Early Maturing ◽  
Sub Saharan

Abstract Background Assessment and effective utilization of genetic diversity in breeding programs is crucial for sustainable genetic improvement and rapid adaptation to changing breeding objectives. During the past two decades, the commercialization of the early and extra-early maturing cultivars has contributed to rapid expansion of maize into different agro-ecologies of sub-Saharan Africa (SSA) where maize has become an important component of the agricultural economy and played a vital role in food and nutritional security. The present study aimed at understanding the population structure and genetic variability among 439 early and extra-early maize inbred lines developed from three narrow-based and twenty-seven broad-based populations by the International Iinstitute of Tropical Agriculture Maize Improvement Program (IITA-MIP). These inbreds were genotyped using 9642 DArTseq-based single nucleotide polymorphism (SNP) markers distributed uniformly throughout the maize genome. Results About 40.8% SNP markers were found highly informative and exhibited polymorphic information content (PIC) greater than 0.25. The minor allele frequency and PIC ranged from 0.015 to 0.500 and 0.029 to 0.375, respectively. The STRUCTURE, neighbour-joining phylogenetic tree and principal coordinate analysis (PCoA) grouped the inbred lines into four major classes generally consistent with the selection history, ancestry and kernel colour of the inbreds but indicated a complex pattern of the genetic structure. The pattern of grouping of the lines based on the STRUCTURE analysis was in concordance with the results of the PCoA and suggested greater number of sub-populations (K = 10). Generally, the classification of the inbred lines into heterotic groups based on SNP markers was reasonably reliable and in agreement with defined heterotic groups of previously identified testers based on combining ability studies. Conclusions Complete understanding of potential heterotic groups would be difficult to portray by depending solely on molecular markers. Therefore, planned crosses involving representative testers from opposing heterotic groups would be required to refine the existing heterotic groups. It is anticipated that the present set of inbreds could contribute new beneficial alleles for population improvement, development of hybrids and lines with potential to strengthen future breeding programs. Results of this study would help breeders in formulating breeding strategies for genetic enhancement and sustainable maize production in SSA.

scholarly journals Breeding maize ( Zea mays ) for Striga resistance: Past, current and prospects in sub‐saharan africa

2021 ◽  
Author(s):  
Abdoul‐Madjidou Yacoubou ◽  
Nouhoun Zoumarou Wallis ◽  
Abebe Menkir ◽  
Valerien A. Zinsou ◽  
Alexis Onzo ◽  
...  
Keyword(s):  
Zea Mays ◽  
Sub Saharan Africa ◽  
Striga Resistance ◽  
Sub Saharan

scholarly journals Transcriptomic Analysis of a Susceptible African Maize Line to Fusarium verticillioides Infection

Plants ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1112
Author(s):  
Humaira Lambarey ◽  
Naadirah Moola ◽  
Amy Veenstra ◽  
Shane Murray ◽  
Mohamed Suhail Rafudeen
Keyword(s):  
Zea Mays ◽  
Fusarium Verticillioides ◽  
Morphological Characteristics ◽  
Sub Saharan Africa ◽  
Chemical Stimulus ◽  
Post Inoculation ◽  
Rna Seq ◽  
Ear Rot ◽  
Maize Line ◽  
Sub Saharan

Maize (Zea mays L.) is a staple crop providing food security to millions of people in sub Saharan Africa. Fusarium verticillioides, an important fungal pathogen, infects maize causing ‘Fusarium Ear Rot’ disease, which decreases maize kernel yield and the quality of the crop harvested. Currently, no African maize line is completely resistant to infection by F. verticillioides. This study investigated an African maize line, Zea mays CML144, infected with F. verticillioides. Analysis of morphological characteristics showed significant differences between mock-infected and infected plants. RNA-sequencing (RNA-seq) was conducted on plants 14 days post-inoculation to identify differentially expressed genes (DEGs) involved in F. verticillioides infection. Analysis of RNA-seq data revealed DEGs that were both significantly up- and down-regulated in the infected samples compared to the mock-infected control. The maize TPS1 and cytochrome P450 genes were up-regulated, suggesting that kauralexins were involved in the CML144 defense response. This was substantiated by kauralexin analyses, which showed that kauralexins, belonging to class A and B, accumulated in infected maize tissue. Gene ontology terms relating to response to stimulus, chemical stimulus and carbohydrate metabolic processes were enriched, and the genes belonging to these GO-terms were down-regulated. Quantitative real-time PCR was performed on selected DEGs and measurement of phytoalexin accumulation validated the RNA-seq data and GO-analysis results. A comparison of DEGs from this study to DEGs found in F. verticillioides (ITEM 1744) infected susceptible (CO354) and resistant (CO441) maize genotypes in a previous study, matched 18 DEGs with 17 up-regulated and one down-regulated, respectively. This is the first transcriptomic study on the African maize line, CML144, in response to F. verticillioides infection.

scholarly journals Incidence of fungi and aflatoxin contamination of maize in Tolon-Kumbungu district of Ghana

2020 ◽  
Vol 28 (2) ◽  
pp. 195-202
Author(s):  
E.K. Aklaku ◽  
E.N.K. Sowley ◽  
M. Ofosu
Keyword(s):  
Zea Mays ◽  
Agar Plate ◽  
Sampling Technique ◽  
Northern Region ◽  
Aflatoxin Contamination ◽  
Sub Saharan Africa ◽  
Rapid Screening ◽  
Food And Agriculture ◽  
Aflatoxigenic Fungi ◽  
Sub Saharan

Maize (Zea mays L.) is an important staple food crop and a source of income to farmers, as well as foreign exchange earner in most countries in sub-Saharan Africa. Its production is hampered by fungal diseases, which also cause contamination with mycotoxins, especially aflatoxin and its associated health hazards. This study sought to isolate and identify aflatoxigenic fungi, as well as detect the presence of Aflatoxin B1 (AfB1) in maize samples obtained from farmers in the Tolon-Kumbungu district in the northern region of Ghana. Twenty farming communities were randomly selected for the study in consultation with the district office of the Ministry of Food and Agriculture (MoFA). Samples were collected from 200 randomly selected maize farmers by the composite sampling technique, for isolation of aflatoxigenic fungi by the agar plate method and the detection of aflatoxin. Aflatoxin was detected in maize samples with the Black light, rapid screening and immunoassay methods. Aspergillus flavus had the highest percentage of occurrence (63.7%); followed by A. niger (16.5%), Rhizopus stolonifer (9.3%), Penicillium spp. (6.9%) and Fusarium oxysporum (3.7%). Farm samples had more aflatoxin than those from stores and markets. Samples of maize from farms in Gbirimani community had the highest aflatoxin contamination of +60 ppb. Concentrations of Afb1 at or above +20 ppb were recorded in all the communities, except in Tinguli. Apart from Voggu, all market samples were free from aflatoxin contamination. Key words: Aflatoxigenic fungi, postharvest, Zea mays

scholarly journals Progress in Breeding Early Maturing Peanut Cultivars with Resistance to Groundnut Rosette Disease in West Africa

2002 ◽  
Vol 29 (1) ◽  
pp. 17-23 ◽  
Author(s):  
B. R. Ntare ◽  
P. E. Olorunju ◽  
G. L. Hildebrand
Keyword(s):  
Virus Disease ◽  
Central Africa ◽  
Management Program ◽  
Sub Saharan Africa ◽  
Yield Potential ◽  
Breeding Lines ◽  
Growing Seasons ◽  
Early Maturing ◽  
West And Central Africa ◽  
Sub Saharan

Abstract Rosette is the most destructive virus disease of peanut (Arachis hypogaea L.) in Sub-Saharan Africa. Resistant cultivars have the greatest potential for minimizing the risk of losses due to the disease. The objectives of this study were to develop and evaluate new peanut breeding lines for reaction to rosette disease and determine their yield potential. Rosette-resistant parents were crossed with early maturing susceptible spanish types. The F2, F4, and F5 generations were grown in a rosette disease screening nursery. A modified bulk-pedigree method was followed in which the populations were grown in bulk until F4. Single plant selections were made in F4-derived F5 progenies. Yield assessment began with F7 lines from 1996 to 1998 growing seasons at three sites. High yielding rosette resistant lines with a maturity range of 90 to 115 d were identified. Some of these new lines produced pod yields significantly higher than the previously developed resistance varieties. Promising lines have been made available to researchers in West and Central Africa and should contribute to an integrated rosette disease management program.

scholarly journals Genetic Gains from Selection for Drought Tolerance during Three Breeding Periods in Extra-Early Maturing Maize Hybrids under Drought and Rainfed Environments

Agronomy ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 831
Author(s):  
Baffour Badu-Apraku ◽  
Oluwafemi Obisesan ◽  
Adeoti Abiodun ◽  
Ebenezer Obeng-Bio
Keyword(s):  
Grain Yield ◽  
Linear Regression Analysis ◽  
Sub Saharan Africa ◽  
International Institute ◽  
Breeding Programs ◽  
Genetic Gains ◽  
Rainfed Conditions ◽  
Early Maturing ◽  
Selection For ◽  
Sub Saharan

Genetic gain studies in a breeding program are very important for measuring the efficiency of the program over a specific period. It also provides breeders with an understanding of the outcomes of the huge investments committed to the breeding programs. This study sought to (i) estimate the gains in grain yield under drought and rainfed conditions and (ii) identify high-yielding and stable hybrids developed in the last two decades under drought and rainfed conditions. Sixty extra-early maturing hybrids developed by the International Institute of Tropical Agriculture (IITA), Ibadan, during three breeding periods: (2008–2010, 2011–2013, and 2014–2016) were assessed under managed drought and rainfed conditions across 14 environments in Nigeria to estimate the genetic gains in grain yield using linear regression analysis. Considerably high genetic gains (4.1%) per year for grain yield was obtained for the extra-early maturing hybrids under drought environments. Six of the top ten hybrids identified were from period 3, an indication of the high genetic gains from selection in period 3. Additionally, two of the top six period 3 hybrids (TZEEI 29 × TZEEI 13) × TZEEI 64 and TZdEEI 64 × TZEEI 54 were found to be the best yielding and most stable across the 14 test environments and were highly recommended for extensive evaluations to warrant their commercialization in sub-Saharan Africa (SSA).

scholarly journals Enhancement of proline content and antioxidant enzyme activities induced by drought stress in maize (Zea mays L.) by application of compost

2020 ◽  
Vol 13 (7) ◽  
pp. 2978-2990
Author(s):  
Atalaèsso Bokobana ◽  
Outendé Toundou ◽  
Komi Odah ◽  
Koffi S.S. Dossou ◽  
Koffi Tozo
Keyword(s):  
Zea Mays ◽  
Antioxidant Enzymes ◽  
Drought Stress ◽  
Water Deficit ◽  
Sandy Soil ◽  
Zea Mays L ◽  
Proline Content ◽  
Sub Saharan Africa ◽  
Antioxidant Enzyme Activities ◽  
Sub Saharan

In sub-Saharan Africa, soil degradation and recurrent droughts are major obstacles to a sustainable agriculture. This study aimed at investigating the effect of compost addition to soil on proline content and activities of the antioxidant enzymes [catalase (CAT), ascorbate peroxidase (APX)] in maize plants, under drought stress conditions. The test was carried out in 20L plastic pots containing either sandy soil or sandy soil with the fertilizer, under natural conditions. The water deficit was induced at male blooming and milky grain stages. Plant irrigation was done by successive weighing of the pots during which the control is reduced to the same weight corresponding to 70% of the useful water reserve (UWR), while the stressed treatment maintains the water content at 30% of the UWR for 10 days. At the end of the stress period, the proline content, the CAT and APX activities in the leaves were determined through a spectrophotometry. The results show an important accumulation of proline and increase in enzymatic activity induced by water deficit in plants grown on compost (p = 0.00000 at p < 0.05). This study provides evidence for a beneficial effect of compost application in enhancing drought tolerance of maize.Keywords: Drought stress; compost; proline; antioxidant enzymes; Zea mays L.

scholarly journals Assessment of Traditional Methods of Controlling Striga on Cultivated Crops in Sudanian Agricultural Zone of Chad

2021 ◽  
Vol 9 (4) ◽  
pp. 242-249
Author(s):  
Gapili Naoura ◽  
Doyam Nodjasse Amos ◽  
Djinodji Reoungal ◽  
Djenaissem Alfred
Keyword(s):  
Crop Rotation ◽  
Sub Saharan Africa ◽  
Mineral Fertilization ◽  
Traditional Methods ◽  
Trap Crops ◽  
Applied Method ◽  
Resistant Varieties ◽  
Rural Services ◽  
Early Maturing ◽  
Sub Saharan

The phytoparasite, Striga spp., is a major biotic constraint to cereals production in sub-Saharan Africa. This study was carried out at station of Bébédjia of Chadian Institute of Agronomic Research for the Development in Sudanian agricultural zone of Chad, on traditional methods of controlling Striga spp. This study helped to find out several methods of controlling Striga among which the most important is the agronomic method including organic and or mineral fertilization, associated crops, crop rotation and the use of false hosts and trap crops. Some farmers cultivated resistant varieties and early maturing varieties to control pest attack and some others used shea flour and herbicide treatment to reduce the effect of Striga on the farm. Most of these methods were applied by farmers from generation to generation, without a thorough study to understand their mechanism. Thus, the listed methods will be analysed by research in station to find out scientific explanations for each applied method. Then experiments will be carried out to evaluate the effectiveness of some methods previously identified by extension rural services in farmers’ area after improvement.  

scholarly journals Genetic analysis of grain yield and agronomic traits of early provitamin A quality protein maize inbred lines in contrasting environments

2019 ◽  
Vol 157 (5) ◽  
pp. 413-433 ◽  
Author(s):  
E. Obeng-Bio ◽  
B. Badu-Apraku ◽  
B. E. Ifie ◽  
A. Danquah ◽  
E. T. Blay ◽  
...  
Keyword(s):  
Grain Yield ◽  
Gene Action ◽  
Agronomic Traits ◽  
Inbred Lines ◽  
Sub Saharan Africa ◽  
Provitamin A ◽  
Heterotic Group ◽  
Quality Protein Maize ◽  
Heterotic Groups ◽  
Early Maturing

AbstractEarly-maturing provitamin A (PVA) quality protein maize (QPM) hybrids with combined drought and low soil nitrogen (low-N) tolerance are needed to address malnutrition and food security problems in sub-Saharan Africa (SSA). The current study's objectives were to (i) examine combining ability of selected early maturing PVA-QPM inbreds for grain yield and other agronomic traits under drought, low-N, optimal environments and across environments, (ii) determine gene action conditioning PVA accumulation under optimal environments, (iii) classify inbreds into heterotic groups and identify testers and (iv) assess yield and stability of hybrids across environments. Ninety-six hybrids generated from 24 inbred lines using the North Carolina Design II together with four commercial hybrid controls were evaluated under drought, low-N and optimal environments in Nigeria in 2016 and 2017. Fifty-four selected hybrids were assayed for PVA carotenoid and tryptophan content. Additive genetic effects were greater than non-additive effects for grain yield and most agronomic traits under each and across environments. The gene action conditioning accumulation of PVA carotenoids under optimal growing conditions followed a pattern similar to that of grain yield and other yield-related traits. The inbred lines were categorized into four heterotic groups consistent with the pedigree records and with TZEIORQ 29 identified as the best male and female tester for heterotic group IV. No tester was found for the other groups. Hybrid TZEIORQ 24 × TZEIORQ 41 was the highest yielding and most stable across environments and should be further tested for consistent performance for commercialization in SSA.

Sign in / Sign up

Export Citation Format

Share Document